Vitamin concentration



Patented Oct. 3, 1939 i -UNITED STATE-s PATENT OFFICEv '2,175,014 i VITAMIN CONCENTRA'1f'ION- Lela E; Booher and Lincoln T. Work,

New York, N.' Y.

Application JulyV 25, 1936, Serial N0. 92,531

12 Claims. (Cl. 167-81) This invention relates to the preparation of a uid Whey as a ley-product from which the vitafood material and more particularly to the prepamin may readily be obtained.

ration of concentrates ot dietary essentials While it is also possible to obtain the vitamin.

known as vitamins. y by synthesis, at present there are practical dini- Among the substances known as `vitamins, culties which make it preferable to produce vita- 6 there is a group commonly designated as the min G by concentration from such natural vitamin B-complex which group, originally be- Sources rather than by synthesis. Since not all lieved to be theanti-neuritic vitamin, has now of the stereoisomeric forms of the sugar group been found to comprise at least three vitamins' in the avine have the same vitamin G potency.

10 namely vitamin B( Bi) or the anti-neuritic vitaonlyv those which have such potency are sought. 10 min; vitamin G or lactoavin and certain other It has been found that the greatest vitamin G avins; and vitamin H described in cci-pending activity is present when the sus-ar group is a application Serial No. 86,305. At least one, and d-IibOSe gIOuP- perhaps both of the vitamins G and H, are con- On the other hand, the concentration of vita.-

35 sidered essential in the preventionv of pellagra min G from natural SelirCeS DI'OViCleS a Clearl- 1.5

l in human beings, black tongue in dogs, and anal- CUE Way 0f PIOViding the desired form 0f the Vitaogous ailments in experimental rats, min and at the same time, ollers an outlet for use Vitamin G is an organic compound havinga 0f the Whey. egformed aS by-PI'OduCtAin the yellow color` and a avine structure. In one of kCheese industry.

its forms it is4 the water-soluble yellow, green- CODCeDtia-ODS Of Vitamin G have been Dl'e- 20 fluorescent pigment of whey or at least, the pig- Pared in Varying degrees 0f potency by Several ment is itself an integral part of thevitamin. Werkeis- 300116K has Sed Whey DOWder and by In the presence of strong acid, the greenuor- SllCCeSSiVe eXIaCiOn With aieOhOi. 2.1691101- escence is absent. The vitamin has been isolated ChiOlOfOrm and ether, has largely eliminated the and structures such as the following have been Sugars, DlOteinS and fats 0f the Whey DOWder t0 25 synthesized and found to possess the specic yield a celleeni'frate Containing Vitamins G and H.

properites of vitamin G and to possess high vita- These haVe been Separated and further Ceneellmin G potency: trated by adsorbing vitamin G on fuller's earth cniwnomecmon l (or Lloyds reagent) from aqueous acid solutions.

Elution of the earth with a solution of water,

l N N i on \C=0 alcohol, and pyridine has yielded good recovery IH I of a concentrated form of vitamin G, but the CHa- 'C/ step has the objection that these organic solvents are expensive, and further that it is very diiiicult to remove the last traces of pyridine. Kuhn This vitamin G activity of ythe cbmpound, as and Others have added the earth directly t0 an indicated by rat growth tests, depends in part acded aqueous Solution 0f Wheyon the stereochemicai configuration of the sugar One disadvantage 0f dem Previous methods group present in the molecule, not all of the s'that ther? are reqr-ed large quantities of ma" 40 stereoisomers of this chemical formula beingterial to be' treated mth expensive solvents' as 40 active, and the active forms varying in degree of -the mst Step ff the process I Vitamin G activity A Othei previous methods have included a crude Vitamin G occurs naturally in 'a number of separation (if the ummm from the other con,"

) food products as for example Skim m egg stituents of the whey by adsorption on fullers White, yeast, liverlean meats, green vegetables, espec andthe like, the nomenclature of a. particular'- gxmi adotbeHdCeif-,gegtd avin being frequently derived from its sourci?, then removed by elution of the earth with a mixhencethe names lactoflavin from milk, ovoflavin ture of pyridine, methyl alcohol and water. The 30- from eggs, hepatonavin from liver. and S0 0n., eiuate is then concentrated, puried, and a sec- 50 Milk is a comparatively good source of the Vita A ond adsorption is carried out,'followed byfurther min. and has been quite commonly used for the vpuriiication and concentration. In such case, preparation of vitamin G'concentrates. In this the quantity of'material to be vtreated Vis greatly case, where casein may beremoved for the proreduced in the rst step by adsorption. How- A duction of paints or of cheese, there is left Va. liq; ever, a large amount of HC1 must be used to make 55 earth. In such case, the whey is made approxi- 4,5' i

the considerable volume of. whey 1 molar and the removal of pyridine is diilcult.

Precipitation of the vitamin with heavy metals such as thallium, silver, and lead at a later stage with ultimate removal of metal has also been employed.

These procedures for the elimination of carintroduces the possibility of ultimate contamination of the product thereby rendering it unsuitable for nutritional purposes. These difculties have heretofore prevented economical quantity production of highly potent concentrates safe for human consumption 'and animal feeding. In lfact, these difliculties have heretofore-been so great as to. cause certain producers to market vitamin G`concentrates of low potency on silicious .earth without removal from the earth. While it has been possible to remove the vitamin G from the earth, heretofore there has existed no satisfactory method for economically producing potent concentrates of the vitamin in relatively large quantities.

It is characteristic of the vitamins that they are all present in very small amounts in the natural products from which they have had to be sepa- `rated. Thisnecessitates the use of large quantities of the raw materials used for the production of the vitamin, if any appreciable amount ofthe vitamin is to be recovered. Using such ylarge quantities of raw material, e. g. whey, it is important to rapidly decrease the amount of material treated during the initial stages by relatively inexpensive operations. This done, it then becomes feasible lto use the more expensive reagents for further concentration and. purification.

Preliminary crude separation of the vitamin from the bulkmaterial may be accomplished by adsorption on fullers earth or other silicious adsorbent such as clay or Filtercel. These are examples of hydrophilic or water-favoring adsorbents,-some of which may be produced synthetcally in the laboratory, as, for instance, silica gel. Adsorption on adsorbent carbon is also possible, in which c ase vitamin H as Well as vitamin G will be adsorbed if present, and there might` also be adsorbed some vitamin B (B1).

Having vin mind the prior art, it is an object of this invention to produce at low cost fromnatural sources, a concentrate of vitamin G free from or in presence .of other vitamins of thevitamin vB- complex.

It is a further object' of this invention to effect this concentration through the -use of procedures and reagents such that there will be no possibility of having injurious reagents present in and vcontaminating theproduced concentrate.

It is a still further object of this invention to provide new low cost-methods to eiect still greater also from the procedure of or strong alkali.

readily. Where not already in aqueous solution,

an aqueous solution orextract is prepared, any

excess fat being separated either mechanically or with the aid of the usual fat solvents. Following this, the solution is taken to the iso-electric point of proteins therein to be precipitated and the thus-l precipitated proteins are separated.-V Y

Then only minor quantities of fat and protein remain, while the vitamin is present with the salts and carbohydrates and other substances which may have been carried thru from the source material. It is found that 4the iso-electric point of casein, pH about 4.6-4.9, is satisfactory acidity for adsorption of vitamin G- on earth, though it is necessary to use a larger amount of adsorbent earth, or to use several batches successively, than would be the case if higher acidity were employed. Filtercel has been found to be a particularly good adsorbent for vitamin G, and as the pH of the solution from which the adsorption takes place is decreased, the amount of Filtercel required for the adsorption is also decreased. However, with Filtercel, it is found that no increase in acidity is required if when working with milk, 6 grams are used per 100 cc. protein-free milk. By use of this amount of adsorbent, a large saving may be made in the cost of treatment-due to the need for using so much less acid. This invention is not restricted to this amount, as more `or less earth or other silicious earths and on different starting materials earth of diierent activity may be used at different efficiencies. n

It is found that the adsorption takes place most eiectively at room temperature or below.

The earth is then filtered and washed to free it of dissolved material in the intersticial lms. In

this invention, departure is made at this point from the procedure of those who dry the earth to sell it as a source of concentrated vitamin G and those who use pyridine According to this invention, we have found that, while the vitamin is adsorbed on the earth at lower temperatures from an aqueous solution, at elevated temperatures, this adsorption is reversed and water orsolutions of the approximate pI-I.of water will serve to elute the vitamin from the earth. In this way a large proportion of Vthe adsorbed vitamin'will be removed by hot Water or' hot aqueous solutions..A The extent of the reversal increases with temperature, hence at high temperatures there will be less volume of eluate for a given recovery.

Superheated water, i. e. under pressure in an autoclave, may be used. Care must be taken not to employ temperatures which, under the conditions of carrying out the procedure, would injure constitutents inthe product. Depending on the starting material, .degree of acidity of the solution, different temperatures are limiting, the elfect of too great temperature under the par- -ticular set of conditions manifesting itself in various ways, for instance, with the destruction.

of' organic materials such as sugars, there may be impairment of the taste of the product, caramelization of the sugars, or even destruction of the vitamin.

The absorbent earth is removed by filtration such as on a. plate and frame lter -press at`elevated temperature and the eluate is concentrated by evaporation, preferably in vacuum.' The earth may be used for further adsorption by recycling.

earth is removed by hot water elution, the -reuse of the earth permits effective'recoveries. The usual engineering devices of countercurrent adsorption and elution may also be used to secure a maximum amount of vitamin in the hot water.

Obviously, good engineering practice over a series of runs calls for the use of comparatively fresh earth on the depleted whey and partially saturated earth in first contact with the whey. Thus a larger quantity of vitamin G will be nally adsorbed on a unit Weight of earth, when the adsorption can attain equilibrium with solution having a greater vitamin G concentration than would be true if the earth were finally in equilibrium with solutions of lesser vitamin G concentration.

Washing technique using cold water to remove the soluble material in the intersticial fluid of the earth cake must also take account of apartlal elution and wash water may have to treated with fresh earth. f

A sequence similar to that used in. adsorption may be followed for elution using hot water; namely to elute earth which has been previously partially eluted and progress to earth containing the larger amounts of vitamin G, thus yielding more concentrated solutions of eluted vitamin G. Such procedures arecommonly practiced in counter-current leaching of ores and precipitates.

For this elution ofthe vitamin from the earth, we have also used hot lime water solution, hot .dilute actie acid, also hot alcohol of diierent strengths. Since vitamin G is destroyed in hot alkaline solutions, solutions of greater alkalinity than that of a saturated solution of calcium hydroxide would normally not be used, particularly where an appreciable time of contact between the Vitamin and solution would be required.

In like manner, hot solutions of other acids may be used toiremove the vitamin from the earth, the kind and concentration of acid to be used depending on the temperature, time of contact, and the effect of the acid on the vitamin or other organic material present. Hydrochloric acid, sulfuric acid (suitable for use in food products) and other common acids might be used, though there is danger, in strong acid solutions, of hydrolyzing the vitamin vor decomposing other organic materials present with the vitamin. In such cases the excess acid might need to be eliminated as by precipitation as with silver or lime due to increase in intensity on increased concentration.

llt is not possible to specify the exact conditions of and ra'nge of alkalinity permitted, as obviously, with lower temperatures, higher aoidities or alkalinities are imposed. Practically, however,

since economy is one of the objects of this iri-v vention, water is obviously the simplest of these` reagents and will hereafter be used as preferred embodiment and for illustrative purposes.v

In the case of the hot lime water, the small amount of lime may be precipitated out after elution by the use of carbon dioxide. In the case of hot aqueous acetic acid, that may be removed by evaporation. The-value in such elution mixtures appears to lie in the effect upon the earth, there being often less ^earth carried intov the eluate than if water is used. In the case of hot alcohol or hot aqueous solutions of alcohol, the alcohol may be evaporated and recovered for re-use. It is also possible to eiect elution in the filter-press using a lesservvolume of elution medium if hot alcohol is first' brought into contact powder.

with the earth and if this is subsequently displaced by hot water.

It should be empasized that such elutions as with pyridine so contaminate the earth that it is not t for re-use Without costly treatment', while 5 y the earth eluted with hot water is free of displacement products. Furthermore it is difficult to completely remove'the pyridine from the concentrate during the process of evaporation and to recover the pyridine in condition for re-use. m

During the process of the concentration of the eluate, appreciable amounts of suspended earth begin to precipitate. It is desirable to remove this earth before the concentration of the solution is so great that significant amounts of Vitamin 1 G are adsorbed upon it. Many of the Well-known coagulating agents will sui-lice for. flocculation of the earth. It is found that dilute acetic acid' lime water, alcohol and the like will produce this eiect. After the earth is separated, it may 2@ be necessary to effect a newelutionjn a manner l 'similar to any of those described. As an alsolids, the concentrates at this stage have yielded 35' from 800 to 1500 units pergrarn of dry solids.

These units for measuring vitamin concentration are based on an arbitrary scale of rat growth under standardized conditions which' are welldefined in the literature.

In other words, the 40 growth rate induced by a certain amount of milk powder would be induced by one rive hundredth of that weight oi concentrate when the concentration was ve hundred fold over that in milk Concentrations have been determined 4'5 by rat-feeding tests and confirmed by colorirnetric tests, since lactoavin has a yellow color.

Hereafter in the specication, concentrations of the vitamin are given in terms of yellow units of these colorimetric measurements, these yellow 5@ units being measured with standard Lovibond glasseslf The depth of the solution for color measurement was 1.0 cm. usually except where intensity of color required lesser or greater depths for accurate measurement and then the color 55 values were recalculated for standard lil cm. depth. There is foundto be a direct proportionality between color intensity and rat growth units.

Use-of colorimetric measurements has the advantage that readings can be made rapidly and 6d easily to indicate the changes in the concentration of vitamin G occurring throughout the various steps.-

We may also use active earth as Lloyds reagent to remove vitamin G from a concentrated eluate 65 from the first adsorption. Vitamin G is adsorbed on Lloyds reagent to a greater extent than the impurities present with it in the solution, so that this adsorption in effect gives further purification. The rst adsorption and elution eliminate a larger proportion of the diluent organic matter and leave concentrations of the other ingredients including vitamin G in certain proportions depending upon the selective action of the earth. I

If these ingredients be concentrated in the eluate by evaporation of much of the water, new ratios of adsorption are established between the ingredients and further concentration of vitamin G may be elected. In such a case, smaller amounts of earth may be used and the elution procedures altered by the use of organic solvents, which earlier in the process would be tooc costly. We do not consider `ourselves restricted to any specific detailsor combinations in further concentrating the rst eluate.

A similar adsorption and elution system may be carried out using active'carbon in place. of earth at any stage in the concentration, the elution medium being preferably a benzene-alcohol mixture on dried carbon containing the vitamin. Due to the azeotropic properties of the water-benzenealcohol system, the water may be removed by dis tillation after wet carbon has been placed in the elution medium. By this process also, the use of objectionable contaminants is avoided for elution agents.

If it be Vdesired to concentrate the vitamin beyond the first stage, the eluate may be concentrated to about 1 to 5 percent solids in solution or any suitable point below the saturation point for the ingredients, and active carbon may be added in suicient amounts to reduce the color substantially. i. e. to adsorb the vitamin G. The carbon is then filtered, washed, and eluted with an organic solvent such as preferably boiling benzenealcohol mixtures. The eluate on evaporation has a potency from 2 to 5 times that of the solids from which it was removed by the carbon. Asv an alternative, the vitamin may also be concentrated further by extraction of the dry solids `with suitable solvents as for example absolute alcohol, benzene-alcohol, etc., which increase the vitamin potency several folddepending upon the amount of solvent, its nature, the extraction temperature, and the like.

As an example of the operation of this invention, there follows data on a test run using skim milk powder. However, the invention of this process is not restricted to the use of skim milk powder or of protein-free milk but may be employed with other vitamin G bearing substances such as yeast, liver, etc. as heretofore mentioned. The use of skim milk powder necessitates the introduction of two steps in the process which would be needless if whey were used. In like manner starting with materials from sources other than milk, slight obvious modifications of' procedure may become necessary. A

To simulate skim milk it was rst necessary to reconstitute the available milk powder into skim milk by mixing 40 lbs. of powdered milk with 300 lbs. of water, or approximately one pound of milk powder to eight pounds of water, giving a product of approximately the same composition as` ordinary skim milk.

The` reconstituted skim milk was heated to about 60 C. and 860 cc. concentrated hydrochloric acid were added to precipitate the casein and other proteins such as lactalbumen and lactoglobin, the final pH of the so-produced protein free milk in this step being about 4.4-4.6.

Heating was further continuedvto about 85 C.

cm. in the Lovibond tintometer, the reading of the protein free milk was .7 yellow unit.

670 grams' of Filtercel were added, the solution having been cooled with ice to about lll-20 C.; and after standing one-half hour, the earth was liltered off. 'I'he filtrate was found to contain' 0.2-0.3 yellow unit. By treatment with more earth or a batch of fresh earth, a better total adsorption resulted. 'I'he earth was then washed with a limited amount of cold water, about onequarter to one-eighth the volume of ltrate from the earth. 'I'he wash became colored to about the extent of this filtrate or a little less.

Live steam was passed into the filter and it condensed as the earthl and press warmed reaching a temperature of around 60-90" C. A solution having a decided yellow color resulted. The,

color-volume units in the original solution from which the casein had been filtered, or 50% of the amount adsorbed on the earth. In this elution, with hot water, about one-half of the vitamin remained on the earth but as the earth had not been injured in its adsorbing property, it

`could be re-used to adsorb more vitamin G and again eluted with essentially complete recovery of the vitamin G taken up the second time. The overall yield through re-use of the earth would therefore approach more closely to 100 per cent. Furthermore, if a counter-current scheme is used whereby the earth nally attains equilibrium with the concentration of vitamin G in the original protein-free milk, that is .7 color unit instead of .3, the amount of vitamin G recoverable on the first elution is much greater than that observed in this sample run.

The eluate was evaporated under, vacuum to solid state and was extracted with small volumes of hot alcohol and the extract evaporated to dryness. Depending upon the amount of alcohol used, potencies ranging from 810 to 1500 rat growth units were obtained. 'lhe larger amount of alcohol dissolved more of the major constituent of the concentrate, lactose, thereby lowering the vitamin G potency. ofthe nal concentrate.

The drawing shows illustrative curves based upon adsorption by Filtrcel at different temperatures, the curves being based on the following test results:

300 gm. of milk powder were added to 2400 cc. v

of distilled water with rapid stirring. The mixture was heated to 80 C. and 585 cc. of 1% HCl were added. The heating was continued until the temperature reached C. The mixture was allowed to cool for about 10 minutes and then filtered.

Four samples of vcc..oi,protein1ree milk prepared as previously described. were treated with various amounts4 of Filtercel at constant' temperature. The Filtercel was allowed to ree main in contact with the solution for` 20 minutes and thenltered as rapidlyas possible. 'I'he -color of this filtrate was determinedl with the Lovibond tintometer, three seriesl of tests being 75 made at remaemnues of 5, 2a", and 40 c.

Series L -Temp. 5 C'.

Y Gram: o! Final Sample color Y ricerca (l mh). l

l1 0. 250 0. 5 Y 2 0. 500 0. 4 Y 3 i. 000 0. 3 Y 4 1. 500 0. 2 Y

`Series B-Temp. 23 C.

Final Grams of Sample color Filtercel (l cm) i 0. 250 0 5 Y 6 500 0 4 Y 7 l. 000 0 3 Y l. 500 0 3 Y Series C-Temp. 0 G.

Final Grams of Sample color Filtercel (1 am) 0 0. 250 o. e Y 10 0.500 0.5 Y ll- 1.000 0.5 Y 12 1. 500 0. 45 Y in plotting the adsorption isotherms, the foilowing values are used:

:zz-Initial color minus final color m--Gramsoi adsorbent per H10 cc. of proteinvfree mill C-Final or equilibrium color so calculating these test data to give valuesior :c

and az/m,. there are obtained the following:

.Series A-Temp. 5

The change'in slope of the isotherme is 'particularly significant, the trend being towards higher values ci the equilibrium color as the temperature is increased. From the viewpoint of adsorption,`the equilibrium color decreases as the temperature decreases and the decrease in the equilibrium color for 'agiven temperature dierence is greater for small values of :lt/m. From the viewpoint of elution. an increase in temtion.

perature gives an increase in equilibrium color.

Thus it will be seen that water at any temperature will remove some vitamin G from earth on which it is adsorbed, but that higher concentrations of vitamin G a're obtained in theelutng medium as the temperature of the elution system is raised. This invention need not be restricted as'to temperature, but is preferably operated at elevated temperatures where the efficiency of elution is greater.

At temperatures higher than that at which adsorption took place, the elution uid will attain a higher color than the residual color in the adsorption equilibrium solution. Thus it will be seen that the adsorption is reversed in water vand certain other solvents, the efficiency of the reversal increasing with increase'in temperature within the limits of stability of the vitamin, or other constituents of the concentrate.

It is thus seen that this invention, involving the use of simple readily available and inexpensive solvents in reducing the volume of vitamin-containing material being Worked with to such a point that it is economically feasible to then apply more expensive solvents, has made commercially possiblethe preparation of concentrates of the vita- The importance of having, not only a concentrate safe for consumption, but also one in adequate quantities, and in highly concentrated form is realized when it is recognized that when the pathological effects of a lack of the vitamin are recognized in a patient, there is generally a lack of appetite which makes feeding of large quanti- Aties oi vitamin-containing materials dicult if not impossible, and at the same time, feeding of the vitamin in concentrated form must often be continued for some time before normal feeding `can be begun.

possible the conversion ci lay-product material intoA useful and valuable production on a scale not heretoiore feasible.

We claim:

i. in a process for the preparation of a concentrate oi vitamin G wherein the vitamin is adsorbeo". from solutions thereof on adsorbent earth, the steps oi eluting vitamin G therefrom by means of .a solvent selected from a group consisting of Water, alcohol, I,dilute acetic acid; e'ecting'the elution and separating the eluate from the atlsorbent at an elevated temperainire with respect to the temperature during the period of adsorp- 2. In a process for the preparation of a con-1 centrate of. vitamin G wherein the vitamin is adsorbed from solutions thereof on a silicious acisorbent, the steps' of eluting vitamin G therefrom by means of a solvent selected from a group consisting oi water, alcohol, dilute acetic acid; effecting the elution and separating the eluate fromthe adsorbent at an elevated temperature with respect to the temperature during the period Aof adsorption.

3. In a, process for the preparation of a concentrate of vitamin G wherein the vitamin is adsorbed from solutions thereof on adsorbent earth, the steps of eluting vitamin G therefrom by treatment with Water at an elevated temperature and of separating the eluate from the earth at a temperature `above that at which the adsorption had taken place.

4. In a process for the preparation of a concentrate of vitamin G wherein the vitamin is adsorbed from solutions thereof on adsorbent earth, the steps of eluting vitamin G therefrom by treatment with an -aqueous solution of alcohol of any concentration at an elevated temperature and of separating the eluate from the earth at a temperature above that at which the adsorption had taken place.

5. In a process for the preparation of `a concentrate of vitamin G wherein the vitamin is adsorbed from solutions thereof on adsorbentJ earth, the steps of eluting vitamin G therefrom by treatment with-dilute acetic acid at an elevated temperature and of separating the eluate from the earth at a temperature above that at which the adsorption had taken place.

6. A process for the preparation of a concenltrate of vitamin G from aqueous solutions thereof which comprises adding an amount of silicious adsorbent material -whereby the greater part of the vitamin is adsorbed from the solution; separat-y ing the silicious adsorbent from the body of the solution; treating the silicious adsorbent with a solvent selected from a group consisting of water, alcohol, dilute acetic acid, at an elevated temperature; separating the solvent from the adsorbent at a temperature above that at which adsorption had taken place; preparing an aqueous solution from the eluate by removing any nonaqueous-soh -vent which may be present; adding an amount of adsorbent carbon to the solution whereby the greater part of the vitamin is removed from the solution; separating the carbon from the solution; eluting vitamin G from the carbon with benzene-alcohol and separating the benzenealcohol from the carbon at an elevatedtemperature; and evaporating the benzene-alcohol from the so-produced solution.

'7. A process for' the preparation of a concentrate of vitamin G from aqueous solutions thereof which comprises adding an amount of a silicious adsorbent material whereby the greater part of the vitamin is adsorbed from the solution; separating the silicious adsorbent from the body of the solution; treating the silicious adsorbent with a solvent selected from aigroup consisting o1' water, alcohol, dilute acetic acid, at an elevated with a solvent selected from a group consisting of water, alcohol, dilute acetic acid, at an elevated temperature; separating the solvent from the adsorbent at a temperature above that at which adsorption had taken place; rpreparing an aqueous solution from the eluate by removing anyV non-aqueous solvent which may be present; precipitating the vitamin from the aqueous solution with an aqueous solution of a heavy metal salt selected from a group comprising silver, lead, thallium; and separating from the solution the precipitate from which the vitamin G may be recovered.

9. A process for the preparation of a concentrate of vitamin G from aqueous solutions thereof which comprises adding an amount of adsorbent earth whereby the greater part of the vitamin is adsorbed from the solution; separating the earth from the body of the solution; treating the earth v With a solvent selected from a group consisting of water, alcohol, dilute acetic acid, at an elevated temperature; separating the solvent from the earth at a temperature above that at which adlsorption had taken place; and concentrating the carbon at an elevated temperature; and evaporating benzene-alcohol from the so-produced solution.

11. A process for the preparation of a concentrate of vitamin G which comprises treating whey solution at substantially normal temperature with an amount of a silicious adsorbent whereby the greater part of the vitamin is adsorbed from the solution; separating the adsorbent from the body of the solution; treating the adsorbent with a solvent selected from a group consisting of water, alcohol, dilute acetic acid, at an elevated temperature; separating the solvent from the adsorbent at a temperature above that at which adsorption had taken place; and concentrating the so-produced solution. Y l2. A process for the preparation of a concentrate of vitamin G which comprises treating a solids-free aqueous extract from yeast at substantially normal temperature with an amount of silicious adsorbent whereby the greater part of the vitamin is adsorbed from the solution; separating the adsorbent from the body of the solu- ,tion; treating the adsorbent with a solvent selected from a group'consisting of water, alcohol, dilute acetic acid, at an elevated temperature; separating the solvent from the adsorbentat a temperature above that at which adsorption had taken place; and conqntrating the so-produced solution. f

yLELA E. BOOHER.

LINCOLN T. WORK. 

